The Authors report their experience about 127 ductal carcinoma in situ (DCIS) of the breast. Guidelines for surgical treatment are: radiological or clinical diagnosis, tumor's extension, histological classification, grading and margin status. At the present the Authors prefer breast conserving surgery with tumor margin's study. They report their experience in the last seven years about sentinel node biopsy. Radiotherapy and endocrine therapy are indicated for selected patients; local recurrence after DCIS therapy is 8,1% on a 6,1 years follow-up.